On Tue, Apr 14, 2026 at 6:24 AM Alexis Lothoré <[email protected]> wrote: > > On Tue Apr 14, 2026 at 12:20 AM CEST, Andrey Konovalov wrote: > > On Mon, Apr 13, 2026 at 8:29 PM Alexis Lothoré (eBPF Foundation) > > <[email protected]> wrote: > >> > >> Add a new Kconfig option CONFIG_BPF_JIT_KASAN that automatically enables > >> KASAN (Kernel Address Sanitizer) memory access checks for JIT-compiled > >> BPF programs, when both KASAN and JIT compiler are enabled. When > >> enabled, the JIT compiler will emit shadow memory checks before memory > >> loads and stores to detect use-after-free, out-of-bounds, and other > >> memory safety bugs at runtime. The option is gated behind > >> HAVE_EBPF_JIT_KASAN, as it needs proper arch-specific implementation. > >> > >> Signed-off-by: Alexis Lothoré (eBPF Foundation) > >> <[email protected]> > >> --- > >> kernel/bpf/Kconfig | 9 +++++++++ > >> 1 file changed, 9 insertions(+) > >> > >> diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig > >> index eb3de35734f0..28392adb3d7e 100644 > >> --- a/kernel/bpf/Kconfig > >> +++ b/kernel/bpf/Kconfig > >> @@ -17,6 +17,10 @@ config HAVE_CBPF_JIT > >> config HAVE_EBPF_JIT > >> bool > >> > >> +# KASAN support for JIT compiler > >> +config HAVE_EBPF_JIT_KASAN > >> + bool > >> + > >> # Used by archs to tell that they want the BPF JIT compiler enabled by > >> # default for kernels that were compiled with BPF JIT support. > >> config ARCH_WANT_DEFAULT_BPF_JIT > >> @@ -101,4 +105,9 @@ config BPF_LSM > >> > >> If you are unsure how to answer this question, answer N. > >> > >> +config BPF_JIT_KASAN > >> + bool > >> + depends on HAVE_EBPF_JIT_KASAN > >> + default y if BPF_JIT && KASAN_GENERIC > > > > Should this be "depends on KASAN && KASAN_GENERIC"? > > Meaning, making it an explicit user-selectable option ? > > If so, the current design choice is voluntary and based on the feedback > received on the original RFC, where I have been suggested to > automatically enable the KASAN instrumentation in BPF programs if KASAN > support is enabled in the kernel ([1]). But if a user-selectable toggle > is eventually a better solution, I'm fine with changing it.
Let's not add more config knobs. Even this patch looks redundant. Inside JIT do instrumentation when KASAN_GENERIC is set.
